Only Pool that doesnt give rejected shares for CCminer is HashHarder !
Suprnova and Harcore lots of rejected with ccminer with nvidia cards.
Yup there seems to be an issue currently with nvidia, can you try to use
--diff-multiplier 256 ?
that should get you accepted shares
otherwise stay on hashharder, they're doing pretty well and its vital to the coin to level out hashrates
Tried -f 256 for mining on suprnova; seemed to help, as I'm getting accepted shares there now.